This invention relates to a device for the thin film application of liquid products, and more particularly a self-contained unit including a reservoir for the liquid product, and an integral applicator for applying and spreading the liquid on a desired surface.
The current devices for the application of liquid films to various surfaces can be broadly divided into two categories: spray generating containers and rub-on systems.
The spray category comprises liquid containers which atomize and spray the liquid product through aerosol, mechanical pump, or squeeze bottle action. Devices in this category are convenient, but severely limited in their ability to atomize and spray viscous liquid in fine, controlled coatings. In addition, the manufacturing cost of these devices results in products of relatively high retail price.
The rub-on category comprises numerous brush, pad, and ball roll-on systems. Devices in this category can be successfully used for the application of viscous liquids, but are not as convenient as sprays, and incur additional drawbacks when applied to several specific product uses.
Rub-on devices which include brushes are typically removably mounted to a container containing a reservoir of liquid. In use, the brushes must be removed from the container, used, returned to the container to be replenished with liquid from the reservoir as often as needed, then sealed back in the container after use. In uses where the applied liquid is sensitive to bacterial degradation (food, cosmetic, medical, etc.), repeatedly returning the brush to a liquid reservoir after contacting outside surfaces creates a health hazard.
Porous or fibrous pads attached to the top of a container defining the liquid reservoir (to spread liquid squeezed through the pad) generally suffer from the same bacterial restraints as brushes. In addition, the thin film of liquid maintained on the surface of such pads during storage is subject to oxidation and hardening if sensitive liquids such as food, oils or cosmetics are used. Also, although it may be desired to wipe the pad clean from time to time, the rough surface of pad is virtually impossible to wipe clean.
With ball or roller roll-on applicators, bacterial contamination of their reservoir can generally be avoided, and such applicators are convenient to use. However, they are relatively expensive, and the rigid ball or roller of such devices will not apply liquid to irregular, hard or very soft surfaces. This precludes their use in applications such as coating cooking utensils with oil, applying condiments to bread, applying medication to a wound, etc.
An object of the present invention is to provide an improved liquid application device which is self-contained and offers quick, easy operation. Another object of the present invention is to provide an improved liquid applicator which can apply thin or viscous liquids in uniform coatings of selected thickness to smooth or irregular surfaces. Still another object of the present invention is to provide an improved liquid applicator which is easy to clean, and protects a reservoir liquid from bacterial attack and oxidation. A further object of the present invention is to provide an improved liquid applicator which is suitable for inexpensive high-speed manufacture.